Simulation of adsorption and flow of pollutants in a column filter: Application to micelle-montmorillonite mixtures with sand

Efficient water remediation requires optimization of adsorptive materials and a utilization of laboratory experiments for designing a large scale filtration. An equation which considers adsorption and desorption according to the Langmuir formalism, and convection is presented and solved numerically for filtration of a solution which includes several pollutants. The competition between two pollutants for adsorption by the filter sites elucidates a case where initially the first one is removed preferentially, whereas later the second one is better filtered, and the emerging solution may include the first pollutant at concentrations above that in the original solution. Experimental results of filtration by a column filled with a mixture of a micelle-montmorillonite complex with sand are presented for two herbicides, bromacil, which is neutral, and sulfentrazone, which is anionic. Elevation of the temperature to 35 degrees C and 50 degrees C did not affect the removal of these herbicides by the micelle-montmorillonite filter, whereas an equivalent filter which included activated carbon (GAC) yielded poor removal. Kinetics of filtration of these herbicides by the micelle-montmorillonite filter was determined. Good simulations and predictions were obtained for the removal of both pollutants from single component solutions and for sulfentrazone when both were simultaneously present. (C) 2012 Elsevier B.V. All rights reserved.